Piston-packing.



JNI/ENTOR. m'hc MF- ATTORNEY Nc. 68|,383. Patented Aug. 27, Iibl.v

W. H. ALISDN. 1

PISTDN PACKING.

(Application led Apr. 29, 1901.)

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UNITED STATES PATENT OFFICE.

WILLIAM I-I. ALISON, OF SAN FRANCISCO, CALIFORNIA.

PISTON-PACKING.

SPECIFICATION forming part of Letters Patent N o. 681,383, dated August 27, 1901. Application filed April 29, 1901. Serial No. 58,058. (No model.)

To all whom, it may concern:

Be it known that I, WILLIAM H. ALIsoN, a citizen of the United States, residing at San Francisco, in the county of San Francisco and State of California, have invented certain new and usefulImprovements in Piston-Packing, of which the following is a specification.

My invention relates to an improved packing for piston-heads, the object of my invention being to provide a packing which will avoid leakage to a greater extent than here tofore. A cylinder will expand unequally in different parts, and in consequence the pistonhead is necessarily made considerably smaller than the cylinder, so that packing is necessary to prevent the steam escaping past the piston-head. Heretofore this packing has been accomplished by a snap-ring moving in an annular recess in the piston-head, either with or without a shoulder. If used without a shoulder, the steam would pack the ring and cause undue friction. If used with a shoulder, the piston-head carries the shouldered ring with it and causes leakage. My invention enables the packing to follow the walls of the cylinder independently of the position of the piston relatively thereto. My invention also permits of ready adjustment for wear of the surface of the packing.

My invention therefore resides in the novel construction, combination, and arrangement of parts for the above ends hereinafter fully specied, and particularly pointed out in the claim.

In the accompanying drawings, Figure lis a diametral section of a packing-ring. Fig. 2 is a similar view of a piston-head, and Fig. 3 is a side View of the packing-ring detached.

Referring to the drawings, l represents the piston-head, 2 the spacing-rings therein, and 3 the follower, bolted to the piston-head by means of the follower-bolts 4. Each space ing-ring has cut therein an annular recess 5, into which is let a compound oating ring, formed of two half-rings 6 bolted together by screws or bolts 7. Said oating ring sections have each an annular shoulder 8, so as to confine a snap-ring 9 in arecess formed by said spaoing-rings sections. The expansive force of the snap-rin g causes it to move snugly against the inner surface of the cylinder, and freedom of movement of the snap-ring laterally with respect to the piston-head is permitted by the fact that said snap-ring has a shoulder 10 engaging the annular shoulder 8 of the floating ring and that the floating ring has a clearance on the outside of the spacing-plate. This clearance enables the ioating ring to move laterally to any desired extent within given limits relative to the piston-head. Thus the packing can follow the inequalities of the inner surface of the cylinder to any necessary extent. When the outer surface of the snap-ring 9 is worn, the shoulder l0 can be turned down sufficient to provide the necessary tightness vof the packing-ring in the cylinder.

In an apparatus of the character described, the combination with the piston4head, of the spacing ring therein having a recess, the oating ring in said recess composed of two sections bolted together, and the snapring having a shoulder and supported in said recess, substantially as described.

In witnesss whereof I have hereunto set my hand in the presence of twosubscribing wit-- nesses.

W. H. ALISON.

Witnesses:

FRANCIS M. WRIGHT, MAY T. BEGLEY. 

